It doesn't sound like it's the doctor making the decision, but the family. He might very well know and be playing the same game his family is. If it were me, I might pretend I didn't know - and I wouldn't bring it up - because I wouldn't want to hurt those close to me by making them think about it. If he's in that situation, he'd probably love to have someone who isn't afraid to talk about it - someone who would listen to him and try to understand. Maybe there's some way you can let him know he can talk without letting on you know something he doesn't.

If it were me, I'd want the opportunity to say goodbye to people.

The doctors may be basing the decision on "Above all, do no harm."